I refused to buy Amazon ebooks when I learned that I didn't own them. I only owned a right to read them (dependent on many legal things).
The price of an ebook has so far been the same as the price of a physical book. Considering the resale value of a book is on average about 50% of the original price, the real price of an ebook for the user with this limitation should be ~50% less than the cost of the paper book. (Not taking into account shipping costs, etc...)
This became real to me when my aunt died. She had purchased thousands of dollars worth of ebooks. Had she purchased physical books, those books would have been donated or resold. At a loss to the publisher, but a gain to the original purchaser and secondary purchaser. (or estate in this case).
Unless I as the purchaser am at least partially compensated for this loss of value by a price decrease, I cannot buy ebooks with a resale limitation.
I bought an ebook from Amazon a few days ago. It asked me "which device do I want it delivered to", and I picked the "download please" (or something worded like that. I downloaded the epub. I could read it on Calibre, on the ReadEra app on my (Amazon-crapware-stripped) Amazon Fire HD, I emailed me to my partner's, "kindle email".
It displayed everywhere nicely. I never purchased books from other locations so I got no opinion on FNAC and the likes, but I never had an issue on Amazon books.
Interesting. I'd never purchased a Kindle book because I assumed I couldn't open it with any app of my choice(I use FBReader on Android)
But it'd be real nice to be able to purchase DRM free ebooks, a la GOG for games.